Electronic equipment housed in a server rack system may generate a large amount of heat. As such, significant airflow may be used to keep the electronic equipment within acceptable thermal limits, such as limits associated with functionality and reliability of servers within the server rack system. To provide airflow, cooling subsystems using fans or blowers have deployed. As heat dissipation requirements of server rack systems increase, more fans may be used or the operating speed of fans may be increased. Increasing the number or operating speed of fans causes an increase in the acoustical noise generated by the fans.
Some server rack systems use acoustical doors to attenuate noise generated by the fans, but acoustical doors have certain drawbacks which may limit their utility. For example, some acoustical doors are quite thick. Accordingly, adding such acoustical doors to a server rack can significantly increase a footprint of the server rack. Data centers tend to have limited floor space. Using server racks with a larger footprint results in narrower aisles between the server racks or fewer rows of server racks within the data center. In addition, shipping such acoustical doors may be more cumbersome and expensive due to their large size. For example, when the acoustical doors are installed on the server rack before shipping, a larger pallet may be used.
Another drawback of the acoustical doors is that they tend to increase airflow impedance. To overcome the added airflow impedance, the fans may be operated at higher speeds. Increasing the fan speed also increases the acoustical noise emission level.